Disease severity of COVID-19 in different phases of the pandemic: Do healthcare workers have better outcomes?

BACKGROUND: This study aimed to characterize and compare the demographics, clinical profile, and COVID-19 outcomes between healthcare workers (HCWs) and non-HCWs COVID-19 patients diagnosed in different phases of the pandemic defined by the vaccine rollout policy and different variants that circulated in South Carolina (SC). METHODS: Extracted from the statewide electronic health record data, we analyzed the clinical outcome of 34,502 HCWs and 1,071,020 non-HCWs adults diagnosed with SARS-CoV-2 between March 2, 2020 to April 14, 2022. Logistic regression models were used to explore the association between different pandemic phases and COVID-19 severity-related outcomes. RESULTS: Substantial reductions in mortality were observed following the vaccine rollout in non-HCWs and HCWs. Compared to the pre-vaccination period, non-HCWs patients diagnosed during post-vaccination with Alpha predominance (adjusted odds ratio [aOR]: 1.10; 95%CI: 1.04–1.16) were more likely to be hospitalized, but the reduced mortality rates were observed in all post-vaccination periods. Regarding HCWs, a reduced mortality rate was only observed in the pre-Alpha (aOR: 0.33; 95%CI: 0.13–0.84) and Omicron periods (aOR: 0.21; 95%CI: 0.05–0.89). CONCLUSIONS: The declining protection effect of vaccines informs the importance of early promotion of the booster dose of the COVID-19 vaccine for HCWs who have more occupational exposure.